1, see the urine test report, generally weak alkaline PH value for girls, weak acid for boys.
2, look at the mother's skin, generally speaking, if it is a girl because of the secretion of estrogen, the mother's skin will be better during pregnancy, and vice versa.
3, look at the characteristics of habits, if you are a second child, you can observe the eating habits of a child during pregnancy and so on.
All the above are personal observations and conclusions, and there is uncertainty. The safest thing is to go to an acquaintance for a B-ultrasound.
My wife is the first son and the second daughter.